I use Firefox mainly but also K-meleon for its speed. But really bothers me about K-meleon is the following:

1) the bookmarks manager is terrible. It is not possible to search bookmarks, and it is not possible to launch a sub-directory of bookmarks into a set of tabs (like you can in FF).

2) No multiline tabs? What are you supposed to do if you have 2 dozen tabs or more open? Would recommend implementing multiline tabs by default.

3) Should have the option to use your scrollwheel to scroll through open tabs when mouse is hovering over tabs.

4) Have something like FF's "Quick Search" bookmarks, which enables you to launch custom web searches by using the address bar (for example, if I type 'g browser' in address bar, it will query Google for 'browser').

K-meleon is a great browser, but could be better.

nevermind 4) above. I imported my FF bookmarks and see that K-meleon does support "Quick Search" bookmarks.

I would also suggest being able to drag-n-drop open tabs, in order to re-arrange them. This is really basic tab (layer) functionality that is absent from K-meleon.

The history management is even worse than bookmarks. You can't even delete items from it! And you can't view them in the order you visited them.